According to the state of the art, in a clocked succession images are recorded of products being transported in succession past the range of a recording means, e.g. of a camera or line reading device, the recorded images are compared with a reference image and the results of the comparison are used to generate signals (alarm or control signals) with which usually a reaction to an irregular product (compared images do not correspond) is initiated, either a reaction by an alarmed operating person or a reaction by one or several correspondingly triggered parts of a device arranged further downstream, e.g. of a switchpoint for eliminating irregular products.
The use of known monitoring methods based on image processing always have an island-like monitoring function in the further processing of products of a printing machine which function must be adapted accordingly as soon as the type of processing changes. Methods for further processing in which several different products of a printing machine are processed simultaneously, e.g. when collating different printed sheets for producing a magazine, several parallel monitoring functions are needed, whereby these e.g. monitor individually the feeding of the different sheet types and must again be individually adapted for production of every given product type. For producing frequently changing product types and especially for producing so called individualized products, the known monitoring methods with image processing are still rather expensive, particularly if, for achieving a satisfactory monitoring, a plurality of image processing functions is required.
Therefore it is an object of the invention to create a monitoring and controlling method based on image processing which method can be applied for the further processing of products of a printing machine, which method is not only simple and safe even when the product types are frequently changed and/or when individualized products are produced but can also be used as controlling method for the mentioned change of product type. A further object of the invention is to create an arrangement for carrying out the method which arrangement is easily adaptable to different printed product types, to different steps of further processing and to different combinations of such steps.